Lisa Downing

Pierre Louis Moreau de Maupertuis’ famous and influential Discours sur les différentes figures des astres, which represented the first public defense of attractionism in the Cartesian stronghold of the Paris Academy, sometimes suggests a metaphysically agnostic defense of gravity as simply a regularity. However, Maupertuis’ considered account in the essay, I argue, is much more subtle. I analyze Maupertuis’ position, showing how it is generated by an extended consideration of the possibility of attraction as an inherent property and fuelled by an understanding of Lockean skepticism about knowledge of real essences that is more nuanced perhaps even than Locke’s own.

Locke’s metaphysical commitments are a matter of some controversy. Further controversy attends the issue of whether and how Locke adapts his views in order to accommodate the success of Newton’s Principia. The chapter lays out an interpretation of Locke’s commitments according to which Locke’s response to Newton on gravity does not require the positing of brute powers and is consistent with his core essentialism. The chapter raises the question of how the hypothesis concerning the creation of matter, alluded to at 4.10.18, fits with these commitments. The chapter concludes that the De grav hypothesis would represent a significant revision to the background metaphysical picture of the Essay, but that nevertheless its attractions to Locke are intelligible and illuminating.

I. Introduction Siris, Berkeley's last major work, is undeniably a rather odd book. It could hardly be otherwise, given Berkeley's aims in writing it, which are three-fold: 'to communicate to the public the salutary virtues of tar-water,'1 to provide scientific background supporting the efficacy of tar-water as a medicine, and to lead the mind of the reader, via gradual steps, toward contemplation of God.2 The latter two aims shape Berkeley's extensive use of contemporary natural science in Siris. In particular, Berkeley's focus on what he calls fire (or aether or light) as a quasiuniversal 'cause' of natural change3 serves these purposes, for the 'activity' of the aether, in his view, can both explain the miraculous virtues of a certain medicine, i.e. tar-water, and reveal God's action and his divine order.4 Berkeley's corpuscular speculations, including his use of fire-theory, are not especially idiosyncratic as natural philosophy. In his theorizing, as Jessop and other have noted, he is heavily indebted to the work of Hermann Boerhaave, the Dutch chemist, botanist, and physician whose teachings were highly influential in mid-eighteenth century Britain.5 Boerhaave, along with other Dutch natural philosophers cited by Berkeley, assigned a central role in accounting for physio-chemical activity to fire, a subtle, insensible particulate substance, sometimes identified with light.

Both Immanuel Kant and Paul Guyer have raised important concerns about the limitations of Lockean thought. Following Guyer, I will focus my attention on questions about the proper ambitions and likely achievements of inquiry into the natural/physical world. I will argue that there are at least two important respects, not discussed by Guyer, in which Locke’s account of natural philosophy is much more flexible and accommodating than may be immediately apparent. On my interpretation, however, one crucial source of a too-limited vision of natural philosophy remains in Locke, where he is appropriately criticized by both Kant and Guyer. My method will be to begin with a distinction that Locke draws in the very first draft of the Essay, between what he calls “the sensible object” and, on the other hand, “the uncertain philosophical cause.” I believe that Locke’s notion of “sensible object,” as opposed to uncertain philosophical cause, retains a central place in his thought in the published Essay, despite the fact thateven though this contrast is never made explicitly there. Tracing the evolution of these two concepts in his thought will allow us to track and better understand his developing views about the relation between the project of the.

George Berkeley, Bishop of Cloyne, was one of the great philosophers of the early modern period. He was a brilliant critic of his predecessors, particularly Descartes, Malebranche, and Locke. He was a talented metaphysician famous for defending idealism, that is, the view that reality consists exclusively of minds and their ideas. Berkeley's system, while it strikes many as counter intuitive, is strong and flexible enough to counter most objections. His most studied works, the Treatise Concerning the Principles of Human Knowledge Principles, for short) and Three Dialogues between Hylas and Philonous Dialogues), are beautifully written and dense with the sort of arguments that delight contemporary philosophers. He was also a wide ranging thinker with interests in religion (which were fundamental to his philosophical motivations), the psychology of vision, mathematics, physics, morals, economics, and medicine. Although many of Berkeley's first readers greeted him with incomprehension, he influenced both Hume and Kant, and is much read (if little followed) in our own day.

While De Motu, Berkeley's treatise on the philosophical foundations of mechanics, has frequently been cited for the surprisingly modern ring of certain of its passages, it has not often been taken as seriously as Berkeley hoped it would be. Even A.A. Luce, in his editor's introduction to De Motu, describes it as a modest work, of limited scope. Luce writes: The De Motu is written in good, correct Latin, but in construction and balance the workmanship falls below Berkeley's usual standards. The title is ambitious for so brief a tract, and may lead the reader to expect a more sustained argument than he will find. A more modest title, say Motion without Matter, would fitly describe its scope and content. Regarded as a treatise on motion in general, it is a slight and disappointing work; but viewed from a narrower angle, it is of absorbing interest and high importance. It is the application of immaterialism to contemporary problems of motion, and should be read as such....apart from the Principles the De Motu would be nonsense.1..